New Planets Discovered

It’s no longer true that “My Very Excellent Mother Just Sent Me Nine Pickles,” as the old mnemonic device goes. But even though Pluto has been officially demoted, the skies have just revealed two new planets to Harvard astronomers.

The widely-publicized HAT-P-1, identified last week by scientists from the Harvard-Smithsonian Center for Astrophysics (CfA), is the largest planet ever detected. But researchers at the same center have also found another so-called “hot Jupiter”—a significant discovery in its own right. Both breakthroughs came with the aid of small amateur telescopes.

The smaller and less-publicized of the pair. TrES-2, is still 30 percent larger in size and mass than Jupiter.

Assistant Professor of Astronomy David Charbonneau designed the telescopes that facilitated the discovery, and he also co-authored the report disclosing the planet’s existence.

He’s better known on campus as the instructor of Science A-47, “Cosmic Connections,” the fourth-largest class in the College last fall.

“Sleuth,” Charbonneau’s telescope, was constructed with four-inch lenses.

The discovery shows that “great science can still be performed using inexpensive equipment,” according to Francis T. O’Donovan, a fifth-year graduate student at Caltech who led the effort that found TrES-2.

O’Donovan corresponded via e-mail from Palomar, Calif., where he is repairing “Sleuth.”

“The equipment is simple, but not the science,” O’Donovan wrote.

Found in the constellation Draco, TrES-2 is one of 200 planets found outside our solar system—but it’s one of only a dozen that can be observed using the “transit method.”

“What’s special about these 12 is they’re the only ones for which we can actually measure the mass and size directly, from which we can get the density, and can guess what they’re made of,” Charbonneau said.

TrES-2, which orbits its star every 2.5 days, is classified as a “hot Jupiter” because it is Jupiter-like in size but un-Jupiter-like in its proximity to its star.

“We think they formed the way our own Jupiter formed...far from their star, and subsequent to their formation, they moved in close to their star,” Charbonneau said.

Luckily for Earthlings, our many-mooned companion in this solar system didn’t follow suit. “If Jupiter had marched in early on, we wouldn’t have a planet to live on,” Charbonneau said.

With two planetary discoveries published within a week of each other, and a handful detected in previous years, the CfA is positioning itself at the forefront of the search for planets outside our solar system. According to Stephen S. Murray, CfA’s deputy director for science, the center is also involved in NASA’s Kepler Mission, which will send a telescope to search for habitable planets. TrES-2 is in the same region that Kepler will peruse.

O’Donovan wrote that a series of disappointments before the final confirmation of TrES-2’s existence at the Keck telescope in Hawaii almost led him to “give up hope.”

“When we were observing at Keck and we realized we had found a planet, it felt like a dream,” he wrote. “And now I can graduate! :-)”

—Staff writer Lulu Zhou can be reached at luluzhou@fas.harvard.edu.